Field of the Invention
The present invention relates to an image forming apparatus, a control method of an image forming apparatus, and a storage medium.
Description of the Related Art
Conventionally, there is an image forming apparatus that feeds sheets from a sheet storing unit such as a sheet feed cassette and prints an image on the fed sheet. Further, there is an image forming apparatus that includes a plurality of sheet storing units. In such a case, distance from the sheet storing unit to a transfer unit is different for each sheet storing unit. For example, if a plurality of sheet feed decks can be attached to the image forming apparatus as optional devices, the distance from the sheet feed cassette included in the image forming apparatus main body to the transfer unit is different from the distance from the sheet feed cassette in the sheet feed decks to the transfer unit. If such an image forming apparatus feeds the sheets by feeding a subsequent sheet on condition that the previous sheet has been fed, intervals between the sheets become excessively long. For example, if an instruction is issued to feed the subsequent sheet from the sheet storing unit disposed far from the transfer unit, after feeding the sheet from the sheet storing unit disposed near the transfer unit, the intervals between the sheets become excessively long. In general, only a minimal predetermined interval for printing the image on the sheets is necessary as the intervals between the sheets. However, in the above-described case, the intervals become longer than such a predetermined necessary interval, so that productivity in printing is lowered.
To reduce such lowering of productivity in printing, a conventional image forming apparatus performs control as described below. A control apparatus (i.e., a controller unit) in the image forming apparatus inputs into a reservation cue, print reservation of a sheet to be fed, before issuing a sheet feed instruction to actually feed the sheet. The image forming apparatus then sets a sheet feed schedule of the sheets according to information about the print reservations input into the reservation cue. The image forming apparatus thus feeds the sheets according to the sheet feed schedule and prints the image on the fed sheets. As a result, the image forming apparatus can previously recognize that the sheet to be fed subsequent to the sheet fed from the sheet storing unit disposed near the transfer unit is to be fed from the sheet storing unit disposed far from the transfer unit. The control unit thus issues ahead of time, an instruction to feed the sheet from the sheet storing unit that is far from the transfer unit, so that the interval between the sheet and the previous sheet can be prevented from becoming excessively long. Such an operation is referred to as advance sheet feed (or preliminary sheet feed) (refer to Japanese Patent Application Laid-Open No. 2005-335929).
On the other hand, there is an image forming apparatus that interrupts a job being executed and then executes a different job (hereinafter referred to as an interrupt job) while interrupting the original job. Such a function is referred to as an interrupt function (refer to Japanese Patent Application Laid-Open No. 2003-228257). Such an interrupt function allows a different job to be executed without waiting for completion of the job being executed, so that a user can quickly acquire a printed product.
However, if there are print reservations of sheets in the image forming apparatus, and the user uses the interrupt function to instruct execution of the interrupt job, the sheet to be printed by executing the interrupt job is not fed until all the sheets that have been print-reserved have been fed. In particular, if a large number of sheets are print-reserved, the time necessary for discharging the printed product corresponding to the interrupt job becomes long. It thus becomes necessary for the user to wait for a long time to receive the printed product.